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We consider the detection and characterisation of brain state transitions, based on ongoing Magneto and Electroencephalography (M/EEG). Here a brain state represents a specific brain dynamical regime or mode of operation, which produces a characteristic quasi-stable pattern of activity at topography, sources or network levels. These states and their transitions over time can reflect fundamental computational properties of the brain, shaping human behaviour and brain function. The Hidden Markov Model (HMM) has emerged as a useful model-based approach for uncovering the hidden dynamics of brain state transitions based on observed data. However, the Geometric distribution of state duration (dwell time) implicit in HMM places highest probability on very short durations, which makes it inappropriate for the accurate modelling of brain states in M/EEG. We propose using Hidden Semi Markov Models (HSMM), a generalisation of HMM that models the brain state duration distribution explicitly. We present a Bayesian formulation of HSMM and use the Variational Bayes framework to efficiently estimate the HSMM parameters, the number of brain states and select among alternative brain state duration distributions. We assess HSMM performance against HMM on simulated data and demonstrate that the accurate modelling of state duration is paramount for accurately and robustly modelling non-Markovian EEG brain state features. Finally, we used actual resting-state EEG data to demonstrate the approach in practice and conclude that it provides a flexible parameterised framework that permits closer interrogation of possible generative mechanisms.

A cross-sectional study was done to determine the prevalence of fasciolosis in cattle slaughtered in abattoirs of Costa Rica and to compare 4 different diagnostic techniques (macroscopic examination of the livers, standard sedimentation of stool, standard sedimentation of the fluid of the gallbladder, and detection of copro-antigen in fecal samples. The sample was divided into two strata of probability of infection (high and low). Considering all the techniques, 11 positive samples from the stratum of high probability were found [prevalence 4.3% (confidence interval CI 95%: 1.8-6.7)] and 1 of the stratum of low probability [prevalence 0.5% (CI 95%: 0.0-1.4)]. When comparing all diagnostic methods, considering the liver condemnation as the reference method, values of sensitivity and specificity respectively of 40 and 100% for the standard sedimentation of stool, 70 and 99.8% for the standard sedimentation of the fluid of the gallbladder and 50 and 100% for the ELISA that detects copro-antigen in feces were obtained. It is concluded that the macroscopic examination of livers in slaughterhouses is a good tool for the monitoring of the disease and that this parasite is distributed heterogeneously in the country. Se realizó un estudio transversal con el objetivo de determinar la prevalencia de fasciolosis en bovinos sacrificados en mataderos de Costa Rica y comparar cuatro técnicas diagnósticas disponibles (inspección macroscópica de hígados, sedimentación estándar de heces, detección de coproantígeno en heces y sedimentación estándar del líquido de la vesí-cula biliar). Se trabajó con dos estratos de probabilidad de infección (alto y bajo). Tomando en cuenta todas las técnicas diagnósticas, se encontraron 11 muestras positivas del estrato de alta probabilidad [prevalencia 4,3% (intervalo de confianza IC del 95%:1,8-6,7)] y 1 del estrato de baja probabilidad [prevalencia 0,5% (IC 95%: 0,0-1,4)]. Al comparar los métodos diagnósticos, tomando el decomiso de hígados como método de referencia, se obtuvieron valores de sensibilidad y especificidad de 40 y 100% para la sedimentación estándar de heces, 50 y 100% para la detección de coproantígeno en heces (ELISA), y 70 y 99,8% para la sedimentación estándar del líquido de la vesícula biliar, respectivamente. Se concluye que la inspección macroscópica de hígados en los mataderos es una buena herramienta de vigilancia de la enfermedad y que esta parasitosis se distribuye de manera heterogénea en el país. Universidad Nacional, Costa Rica Escuela de Medicina Veterinaria

El rash es un efecto secundario común asociado al uso de fármacos antiepilépticos. La frecuencia de rash con fenitoína se ha estimado en un 5,9% y asciende a un 25% en pacientes que han presentado rash con otro fármaco antiepiléptico. La anemia aplásica es una anomalía adquirida de las células madre hematopoyéticas caracterizada por pancitopenia de la sangre periférica y médula ósea hipocelular. Los pacientes tratados con fenitoína presentan un riesgo 3,5 veces mayor de desarrollar anemia aplásica. Presentamos el caso de una mujer de 70 años que desarrolló dos reacciones adversas severas y simultáneas a la fenitoína: un exantema maculopapular pruriginoso con compromiso de mucosas y una anemia aplásica. Ambas condiciones se resolvieron completamente con la suspensión del fármaco. Rash is a common side effect associated with antiepileptic drugs. The rate of a phenytoin rash is 5.9% and increases to 25% in those with another antiepileptic drug rash. Aplastic anemia is an adquired hematopoietic stem-cell disorder characterized by pancytopenia of the peripheral blood and hypocellular bone marrow. The use of phenytoin is associated with a 3.5 fold increased risk of aplastic anemia. We report a case of a 70-year-old woman who developed two severe adverse reactions simultaneously with phenytoin: a maculopapular pruritic rash with involvement of mucous and an aplastic anemia. Both conditions normalized after phenytoin withdrawal.

El rash es un efecto secundario comun asociado al uso de farmacos antiepilepticos. La frecuencia de rash con fenitoina se ha estimado en un 5,9% y asciende a un 25% en pacientes que han presentado rash con otro farmaco antiepileptico. La anemia aplasica es una anomalia adquirida de las celulas madre hematopoyeticas caracterizada por pancitopenia de la sangre periferica y medula osea hipocelular. Los pacientes tratados con fenitoina presentan un riesgo 3,5 veces mayor de desarrollar anemia aplasica. Presentamos el caso de una mujer de 70 anos que desarrollo dos reacciones adversas severas y simultaneas a la fenitoina: un exantema maculopapular pruriginoso con compromiso de mucosas y una anemia aplasica. Ambas condiciones se resolvieron completamente con la suspension del farmaco.

Tuberculosis (TB) is a worldwide infectious disease, caused by Mycobacterium tuberculosis (Koch bacilli), that has re-emerged since the decade of the 80's in relation to the pandemic of HIV infection. Chile has one of the lowest TB prevalence rates in Latin America. In children, TB exhibits some differences from adult disease in terms of pathogenesis, clinical manifestations and probability of progression from the infected state to disease, making it more difficult to diagnose and increasing the likelihood of developing the disease once the infection is acquired. There is a National Program for the Prevention and Control of TB that allows us to develop prevention and chemoprophylaxis strategies. This article summarizes these strategies to guide the study and management of children in contact with TB patients.

La tuberculosis (TBC) es una enfermedad de distribución mundial, producida por Mycobacterium tuberculosis (bacilo de Koch), que ha re-emergido desde la década de los 80 en relación a la pandemia de VIH. Chile es uno de los países latinoamericanos con menores tasas de prevalencia de TBC. En los niños, la TBC presenta algunas características distintas al adulto en cuanto a patogenia, clínica y probabilidad de progresión desde una infección latente a enfermedad, siendo más difícil realizar el diagnóstico y mayor la probabilidad de desarrollar enfermedad una vez infectados. Existe un Programa Nacional de Prevención y Control de la TBC que nos permite plantear estrategias de prevención y quimioprofilaxis. Este artículo esquematiza estas estrategias para orientar el estudio y manejo de niños que entran en contacto con pacientes con TBC.

Introducción: El SAHOS presenta una alta prevalencia en estudios internacionales, con importantes repercusiones en los sistemas cardio, cerebrovascular y en la calidad de vida de las personas. Método: Estudiamos prospectivamente a los pacientes enviados para Polisomnografia (PSG) a nuestro laboratorio de sueño, en un período de 6 meses. Previo consentimiento informado, se les aplicó la Escala de Somnolencia de Epworth (EE) y un Cuestionario de Sueño. Fueron entrevistados 100 pacientes, excluyéndose 3 por no haberse realizado PSG y 2 que no completaron la EE. Resultados: Se analizaron 95 pacientes, 89,5% hombres, edad promedio 47,4± 12,5 años, obesidad en 49,5%, EE mayor de 11 en 56,8%, ronquido en 93,7%, pausas respiratorias en 68,4%, somnolencia diurna excesiva en 57,9%, cansancio al despertar en 86,3%o. La PSG no demostró SAHOS en 14,7%, hubo 27,4% con SAHOS leve, 21 %> moderado y 36,8%> severo. Las variables presencia de pausas respiratorias observadas por la pareja e índice de masa corporal (IMC) predicen la ausencia de SAHOS severo, con una sensibilidad de 87% y especificidad de 50%. Conclusión: En la evaluación de pacientes con sospecha de SAHOS, la no observación de pausas respiratorias durante el sueño por parte de la pareja y el IMC menor de 30 Kg/m² hacen menos probable que exista un SAHOS severo. Introduction: Obstructive sleep apnea syndrome (OSAS) is a common disease associated with significant morbidity, including excessive daytime sleepiness, cardiovascular disease and stroke. Method: We studied prospectively the patients sent to our sleep laboratory for polysomnography (PSG) during 6 months. One-hundred patients were interviewed with a sleep questionnaire, 3 of them were ruled out because the lacking of PSG and 2 who no completed the Epworth sleep scale (ESS). Results: Out of the 95 patients, there were 85 men and 10 women, with a mean age of 47.4 ± 12.5 years, obesity was found in 42.5%, an ESS greater than 11 points was found in 56.8%, loud snoring in 93.7%, breathing cessation in 68.4%, excessive daytime somnolence in 57.9%. PSG revealed no OSAS in 14.7%, slight OSAS in 27.4%, moderate OSAS in 21% y severe OSAS in 36.8%. Body mass index and breathing cessation reported by the couple had the highest discriminative power with a sensibility of 87% and specificity of 50% for ruled out severe OSAS. Conclusion: A severe OSAS is less probable when there is absence of breathing cessation during sleep reported by the couple and an IMC

Introduccion: El SAHOS presenta una alta prevalencia en estudios internacionales, con importantes repercusiones en los sistemas cardio, cerebrovascular y en la calidad de vida de las personas. Metodo: Estudiamos prospectivamente a los pacientes enviados para Polisomnografia (PSG) a nuestro laboratorio de sueno, en un periodo de 6 meses. Previo consentimiento informado, se les aplico la Escala de Somnolencia de Epworth (EE) y un Cuestionario de Sueno. Fueron entrevistados 100 pacientes, excluyendose 3 por no haberse realizado PSG y 2 que no completaron la EE. Resultados: Se analizaron 95 pacientes, 89,5% hombres, edad promedio 47,4± 12,5 anos, obesidad en 49,5%, EE mayor de 11 en 56,8%, ronquido en 93,7%, pausas respiratorias en 68,4%, somnolencia diurna excesiva en 57,9%, cansancio al despertar en 86,3%o. La PSG no demostro SAHOS en 14,7%, hubo 27,4% con SAHOS leve, 21 %> moderado y 36,8%> severo. Las variables presencia de pausas respiratorias observadas por la pareja e indice de masa corporal (IMC) predicen la ausencia de SAHOS severo, con una sensibilidad de 87% y especificidad de 50%. Conclusion: En la evaluacion de pacientes con sospecha de SAHOS, la no observacion de pausas respiratorias durante el sueno por parte de la pareja y el IMC menor de 30 Kg/m2 hacen menos probable que exista un SAHOS severo.

Introducción: Los trastornos del sueño, especialmente el Síndrome de Apneas del Sueño (SAS), presentan una alta prevalencia internacional, pero no existen estudios en Chile. Método: Durante un período de 6 meses, se ingresó progresivamente una muestra randomizada de 180 pacientes mayores de 18 años (135 mujeres, 45 hombres) que consultaron en un Centro de Salud Familiar, para evaluar la frecuencia de trastornos de sueño con la Escala de Somnolencia de Epworth y un Cuestionario de Sueño especialmente diseñado que incluyó: estado nutricional, enfermedades médicas, uso de medicamentos, tabaco y alcohol, hábitos de sueño, ronquido, pausas respiratorias, insomnio, somnolencia diurna excesiva y síntomas depresivos. Resultados: Se encontró hipertensión arterial en 37,2%, diabetes en 11,1%, dislipidemia en 19,4% y tabaquismo en 34,4%, IMC > de 30 kg/m² en 38,3%, Epworth > 15 en 13,9%, ronquido en 56,7%, pausas respiratorias en 21,7%, somnolencia diurna excesiva en 29,4%, dificultad en la iniciación (21,7%) y mantención del sueño (21,7%). Tristeza persistente y/o pérdida de interés en sus actividades o falta de disfrute en el último mes fue referida por 43,8% de los pacientes. Conclusión: La alta frecuencia de trastornos del sueño encontrados, hacen necesario incluirlos en la planificación de programas de salud en nuestro país, para su adecuado diagnóstico y tratamiento, especialmente considerando el que algunos de estos trastornos constituyen factores de riesgo para enfermedades vasculares cardíacas y cerebrales. Introduction: Sleep disorders, especially sleep breathing disorders, have not been well studied in the patients attending a family health center in Chile. Sleep breathing disorders have been linked to cardiovascular and cerebrovascular diseases, which are important causes ofmorbidity and mortality. Method: We studied a randomized sample of 180 adult patients (135 women and 45 men, with a mean age of 45.6 years) consulting a public family health center with the Epworth Sleepiness Scale and a Sleep Questionnaire which include assessment ofobesity medical conditions, medications and smoking habit, blood pressure, sleep habits, snoring, breathing cessation, insomnia, daytime sleepiness and depressive symptomatology Results: Hypertension wasfound in 37.2%, diabetes in 11.1%, dislipidemia in 19.4%, smoking in 34.4%. Body mass index > of30 Kg/m² wasfound in 38.3%). Twentyfivepatients (13.9%>) had an Epworth score >ofl5. Loud snoring was reported in 56.7%>. Breathing cessation was reported by the spouses in 21.7%>. Difficulty for sleep initiation was present in 21.7% and to maintain sleep in 21.7%. Daytime sleepiness was present in 29.4%. Twelve patients (6.7%) had the highest score in a visual analog scale for daytime somnolence. An affirmative answer for persistent sadness or low mood and loss ofinterest or pleasure in the last month was reported by 43.8% ofthe patients. Conclusión: It is noteworthy the high frequency of undiagnosed sleep disorders found in a population consulting by others pathologies. These results would be useful for the planning of public health programs which should include sleep disorders.

Introducción: Los trastornos del sueño, especialmente el Síndrome de Apneas del Sueño (SAS), presentan una alta prevalencia internacional, pero no existen estudios en Chile. Método: Durante un período de 6 meses, se ingresó progresivamente una muestra randomizada de 180 pacientes mayores de 18 años (135 mujeres, 45 hombres) que consultaron en un Centro de Salud Familiar, para evaluar la frecuencia de trastornos de sueño con la Escala de Somnolencia de Epworth y un Cuestionario de Sueño especialmente diseñado que incluyó: estado nutricional, enfermedades médicas, uso de medicamentos, tabaco y alcohol, hábitos de sueño, ronquido, pausas respiratorias, insomnio, somnolencia diurna excesiva y síntomas depresivos. Resultados: Se encontró hipertensión arterial en 37,2%, diabetes en 11,1%, dislipidemia en 19,4% y tabaquismo en 34,4%, IMC > de 30 kg/m² en 38,3%, Epworth > 15 en 13,9%, ronquido en 56,7%, pausas respiratorias en 21,7%, somnolencia diurna excesiva en 29,4%, dificultad en la iniciación (21,7%) y mantención del sueño (21,7%). Tristeza persistente y/o pérdida de interés en sus actividades o falta de disfrute en el último mes fue referida por 43,8% de los pacientes. Conclusión: La alta frecuencia de trastornos del sueño encontrados, hacen necesario incluirlos en la planificación de programas de salud en nuestro país, para su adecuado diagnóstico y tratamiento, especialmente considerando el que algunos de estos trastornos constituyen factores de riesgo para enfermedades vasculares cardíacas y cerebrales.

Background: The restless legs syndrome (RLS) is a movement disorder characterized by an imperative urge to move the legs, associated with paraesthesias, motor restlessness and worsening of symptoms at night with at least partial relief by activity. Its prevalence ranges between 2-15% of general adult population and 20-30% of uremic patients. Aim: To evaluate the frecuency and the clinical features of RLS in a sample of general adult population and in uremic patients, in Chile, correlating it with biochemical parameters. Method: 100 relatives of outpatients and 166 uremic patients undergoing chronic haemodialysis were interviewed assessing the presence and severity of RLS according to current diagnostic criteria. Biochemical parameters assessed were hematocrit, serum ferritin, phosphate, intact parathyroid hormone (iPTH) levels. Results: 13% of the general population sample was affected, 15% of them were severe. Forty three cases were found among uremic patients (25.9%) (p

Background: The restless legs syndrome (RLS) is a movement disorder characterized by an imperative urge to move the legs, associated with paraesthesias, motor restlessness and worsening of symptoms at night with at least partial relief by activity. Its prevalence ranges between 2-15% of general adult population and 20-30% of uremic patients. Aim: To evaluate the frecuency and the clinical features of RLS in a sample of general adult population and in uremic patients, in Chile, correlating it with biochemical parameters. Method: 100 relatives of outpatients and 166 uremic patients undergoing chronic haemodialysis were interviewed assessing the presence and severity of RLS according to current diagnostic criteria. Biochemical parameters assessed were hematocrit, serum ferritin, phosphate, intact parathyroid hormone (iPTH) levels. Results: 13% of the general population sample was affected, 15% of them were severe. Forty three cases were found among uremic patients (25.9%) (p

Recently a number of techniques have been developed that stimulate people to act towards specific objectives. These include persuasive technologies, gamification, user experiences, and various methods and tools used in open-source and other communities to encourage and organize participation. After surveying various examples of such applications, we generalize these approaches by proposing a new theoretical framework. The basic concept is a mobilization system, defined as an ICT environment that motivates and coordinates the actions of people, so as to increase their focus and commitment, while minimizing distraction, hesitation and procrastination. We then analyze the fundamental mechanisms of (individual) motivation and (collective) coordination, starting from Csikszentmihalyi's concept of flow and the mechanism of stigmergy. The basic requirements are clear goals in line with real needs, immediate and rich feedback, challenges in balance with the user's skill levels, and a shared workspace in which all tasks and results are registered for every contributor to see. We conclude our review of mobilization systems by pointing out their potential dangers, such as addiction and political or commercial exploitation, as well as their potential benefits, in domains such as work, health, education and research.

Cook and Garduno Freeman argue that social networks such as Flickr function as public repositories of personal photography that challenge and democratize the authority of traditional institutions of memory, like libraries and museums. Vernacular photography on these systems increases the visibility of individual's self-representation. In contrast to institutional collections, members on Flickr self-select the subject matter in their photographic contributions, the methods of representation, and the modes of participation.